The invention relates to improvements in ice cube making machines of the type employing a refrigeration system with an evaporator having a plurality of small elements which project into a water pan. The cubes form around the elements and during the harvest cycle are released from the elements into the pan by circulating hot gas through the elements to melt the adjacent surfaces of the cube. The cubes are harvested from the pan by tilting the pan to dump the cubes into a storage bin.
It is known that agitation or movement of water during the freezing thereof is necessary to form the highly preferred clear ice cubes rather than cloudy or opaque cubes formed in home refrigerators. Various techniques have been employed to accomplish agitation. In the Lindenberg U.S. Pat. No. 3,027,731, a rotary agitator containing a rotating shaft and rotating paddle elements which move in between the freezing elements causes agitation of the water. Because the paddles move into and above the water in the water pan during rotation thereof, dripping water from the raised paddles splashes and causes disturbance upon the surface of the water which results in a non-uniform irregular surface on the tops of the ice cubes at the water surface.
Other techniques employed for agitation of water in the ice making pan include the use of pumps which circulate and recirculate the water. Clogging and other maintenance problems of the pumps are disadvantages of this approach.
Ice making machines require some type of sensor to stop the freezing cycle or start the harvest cycle. In the Lindenberg U.S. Pat. No. 3,027,731, the freezing cycle is stopped when the rotating paddles strike forming ice cubes to cause a torque which displaces a pivoted motor to actuate an electrical switch and stop the freezing cycle.
The foregoing arrangement provides an impositive control of the cube size. Wear of the paddles can change the point in time during the freezing cycle when the paddles strike the developing cubes and thus change the thickness of the cubes. Systems of this type are not easily controlled to afford selection of different cube thicknesses.